Short-term Debt	3 Months Ended
Dec. 31, 2012
Debt Disclosure [Abstract]
Short-term Debt	Short-term Debt Our short-term debt obligations are comprised of commercial paper borrowings. Commercial paper borrowings outstanding were $253.0 million at December 31, 2012 and $157.0 million at September 30, 2012. At December 31, 2012, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.27 percent and nine days, respectively. At September 30, 2012, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.27 percent and six days, respectively.

Short-term Debt

3 Months Ended

Dec. 31, 2012

Our short-term debt obligations are comprised of commercial paper borrowings. Commercial paper borrowings outstanding were $253.0 million at December 31, 2012 and $157.0 million at September 30, 2012. At December 31, 2012, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.27 percent and nine days, respectively. At September 30, 2012, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.27 percent and six days, respectively.